Condensed Consolidated Statements of Comprehensive Loss (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Statement of Partners' Capital [Abstract]
Net loss	$ (34,681)	$ (26,525)
Other comprehensive income (loss), net:
Change in unrealized gain/loss on available-for-sale securities	(12)	(69)
Foreign currency translation adjustment	1,254	13
Other comprehensive income (loss)	1,242	(56)
Total comprehensive loss	$ (33,439)	$ (26,581)